Chinese cruise operators used to make loads of money by offering tours on the border of the Yalu River. The tensions between China and North Korea now threaten their business / Nina Trentmann

by Nina Trentmann, Special for USA TODAY

by Nina Trentmann, Special for USA TODAY

DANDONG, China -- An early-morning mist rises from the icy waters of the Yalu River where the ruins of a bridge that once connected China and North Korea stands. A North Korean soldier in a greenish overcoat and cap walks up and down, keeping guard. On the Chinese side, two soldiers armed with machine guns stare across.

Nearby is a large black-and-white photograph of communist China founder Mao Zedong shaking hands with Kim Il Sung, founder of North Korea. But trade and traffic between the two allies are far less active here since North Korea moved forward with nuclear tests that the United Nations has condemned as a violation of international law.

"We used to go to North Korea for a day from here," says Ibell Liu, 31. Now, "the Chinese are not allowed into North Korea anymore."

China is getting pressured by Europe and the United States to rein in North Korea's communist regime, which is highly dependent on China for its survival. China's recent naming of a new leader, Xi Jinping, has given the West hope that China will finally squeeze North Korea into complying with U.N. resolutions as well as pacts signed with the United States in which it agreed to end its nuclear program.

Whether China can do it, or even wants to, is a question. Beijing voted for U.N. sanctions against North Korea in January following a December missile launch by the regime of Kim's grandson, Kim Jong Un, but it has blocked more serious action.

"A number of U.S. scholars, including longtime China watchers, believe that Beijing in reality has little if any functional influence over Pyongyang," Michael Auslin, director of Japan studies at the American Enterprise Institute in Washington, said in testimony last week before the U.S.-China Economic and Security Review Commission. "Others assume that Beijing has decided that the existence of an erratic, anti-American regime in control of the northern half of the Korean Peninsula is preferable for its geopolitical goals to other alternatives."

China is North Korea´s most important trading partner. More than half of the goods that the North Korean regime needs desperately to survive -- food, fuel, basics -- enters North Korea from this trading port, a city of 800,000 Chinese and several thousand North Koreans in Liaoning province.

Some here say the slowdown of trade is an intentional expression of Beijing's anger with Pyongyang over its nuclear program.

Chinese tourists, a rare source of hard currency for North Koreans, were recently prohibited from visiting North Korea here. Now all tourism into the isolated country has to go via Pyongyang, the North Korean capital.

"It used to be just the Americans who had to go via Pyongyang," says Nagesh Reddy, 29, a tourist from India. "Now, everyone who wants to travel to North Korea needs to fly into Pyongyang."

On this day, Reddy had to be content to take pictures of the ruined bridge -- destroyed by an American air-raid during the Korean War and never rebuilt -- and a deserted amusement park on the North Korean shore, put there to lure tourists with money.

Since Tuesday, the day that North Korea officially announced another successful nuclear test, the atmosphere in Dandong was not festive, despite the recent celebrations for the Lunar New Year. Tourist numbers are down, locals say.

"This is of course bad for business," said Liu Cheng, a taxi driver from Dandong. The 37-year-old earns money by driving tourists around.

"Most of them want to go up north," he said. North of Dandong, the Yalu River becomes narrower. Visitors on the China side like to head north to get a closer look at what President George W. Bush said was a member of the world's "Axis of Evil," along with Iran and Saddam Hussein's Iraq. Barbed wire and a high fence illustrate why the country is sometimes referred to as "the Hermit Kingdom," a place where starvation is rampant and modern technology rare.

Such despair brings out the curiosity seekers. For half a day, Liu charges about $96 to take visitors to scenic spots. Dandong has more than 70 hotels. One of them is a four-star Crowne Plaza that promises "the best views of North Korea" for about $55 a night.

One of the places that Liu normally takes his customers to is the Great Wall at Hushan. The ancient fortress offers views on a North Korean village, a small settlement with brownish, one-story buildings, all looking very much the same. The village has one unpaved street.

On this day, the parking lot across from the village is nearly empty as Liu enters with his orange cab. The celebration of the Spring Festival, the most important holiday of the year in China, keeps many offices and shops closed.

A handful of street vendors sell cigarettes in red packages and small pins depicting Kim Jong Il, the former North Korea leader known as "Dear Leader," whose death was announced in December 2011. He succeeded his father, "Great Leader" Kim Il Sung, and was succeeded by son Kim Jong Un.

The Santieli restaurant, one of a few in Dandong, is operated by the North Korean Consulate on the Chinese side. Waitresses wear traditional, full-length dresses in pink and blue. Some are dressed in violet jackets and skirts, making them look like stewardesses from the 1970s.

They talk little while serving, speaking mostly Korean but some Chinese and refusing to be quoted. A menu on the wall offers North Korean dishes and one can smell kimchi, cabbage spiced with chili that is a traditional dish for Koreans.

"That´s all they have in North Korea," says Ibell Liu, who used to travel to North Korea frequently. "It´s still a country which lacks nearly everything."

The trucks that cross the bridge into North Korea are loaded with goods from China but return nearly empty.

"The North Koreans produce nothing that we might be interested in," Ibell Liu says.

Her mother is friendly with a North Korean woman with whom she worked at a factory in Dandong. The friend married a Chinese man, and when asked, she refuses to be interviewed out of fear that she will endanger her family members who still live on the North Korean side of the riverbank.

In Dandong there are an estimated 20,000 to 30,000 North Koreans. Most of them live on the banks of the Yalu River. Some are here illegally and cannot send their children to school. In some cases, Chinese authorities will apprehend North Koreans and return them to the other side, where they likely face a horrible imprisonment, according to rights groups such as Human Rights Watch.

Some worry that China may round up North Koreans here and send them back as an example of displeasure with North Korea's leadership. Ibell Liu doubts it.

"Chinese authorities most often react by keeping one eye open, one eye shut," she says.